I want to merge logs so both profiles won't perform actions on the same URLs
But I don't really want to use 'Share across accounts' funcionality

Global processed logs (action tab specific)
Global logs allow you to sync already processed items for multiple accounts without having to perform a shared account action. Thus the specified accounts will never action the same items
regardless of whether performing a single account action, a multi account action or a shared account action.
To specify a global log, select your accounts and specify to assign a global log, give the global log a name and your done. Any account at any time can
be assigned to the global log, by repeating the above and giving the same name. Any account can belong to any number of global logs. But then things can get complicated so if you don't want to do it, don't worry about it.
But you can have acc1 and acc2 using a global log and acc2 and acc3 and acc4 on another.

I want to merge logs so both profiles won't perform actions on the same URLs
But I don't really want to use 'Share across accounts' funcionality

Global processed logs (action tab specific)
Global logs allow you to sync already processed items for multiple accounts without having to perform a shared account action. Thus the specified accounts will never action the same items
regardless of whether performing a single account action, a multi account action or a shared account action.
To specify a global log, select your accounts and specify to assign a global log, give the global log a name and your done. Any account at any time can
be assigned to the global log, by repeating the above and giving the same name. Any account can belong to any number of global logs. But then things can get complicated so if you don't want to do it, don't worry about it.
But you can have acc1 and acc2 using a global log and acc2 and acc3 and acc4 on another.

That's it. The reason you give a name(id) is, if you add an account later that you want to sync with the group, simply right click >global logs > add > specify the previous name(id) and then the new account knows about all previous processed logs